type alignment: Use type_length_units

type alignment: Use type_length_units

The type alignment value is returned in 8-bit-bytes instead of target
memory addressable units.  For example, on a target with 16-bit-bytes
where sizeof(int) == 1 (one addressable unit), alignof(int) currently
returns 2.  After, this patch, it returns 1.

gdb/ChangeLog:

	* arch-utils.c (default_type_align): Use type_length_units.
	* gdbtypes.c (type_align): Use type_length_units.